Carcinoid tumours

Carcinoid syndrome

usually occurs when metastases are present in the liver and release serotonin into the systemic circulation
may also occur with lung carcinoid as mediators are not 'cleared' by the liver

Features

flushing (often earliest symptom)
diarrhoea
bronchospasm
hypotension
right heart valvular stenosis (left heart can be affected in bronchial carcinoid)
other molecules such as ACTH and GHRH may also be secreted resulting in, for example, Cushing's syndrome
pellagra can rarely develop as dietary tryptophan is diverted to serotonin by the tumour

Investigation

Management